Notes on the Canon FD 20-35mm f/3.5L on the A7

So I recently picked up an ultra-wide zoom for my A7 in the form of a Canon FD 20-35mm f/3.5L. (and now I have a nice Canon FD trinity: 20-35mm , 85mm, & 135mm). I haven't yet had an opportunity to truly put it through its paces, but here are some initial thoughts:

Lots of CA at all apertures on the outer portions of the frame. Thankfully, that's easily correctable in LR.

Vignetting isn't an issue at f/5.6 and smaller.

Excellent resolution in the center wide open out to about 2/3rds the frame for all focal lengths--even the edges are decent.

To the extent that there is out of focus blur (it is an ultra wide after all), the quality of that blur is top notch.

Corners are super soft at 20mm and 24mm unless you stop down to at least f/8.

For landscape work, f/11 is ideal.

Serious mustache distortion at 20mm

Thankfully, the built in profile for the Canon EF 17-40mm does quite a good job at correcting it. The Canon 20mm f/2.8 profile works nearly as effectively.

Thanks Mike for posting this. I always wondered about this lens. I have the 20mm f2.8 and the 35mm f2 so Ive never 'needed' this one but it does render very nicely. I wish Canon had made a 35mm F1.4L in a FD mount back then because I would own it, but alas they did not.